The agricultural industry, and in particular the citrus juice concentrate industry, depend heavily on the harvesting of fruits from trees which are grown in commercial orchards. In the past, this harvesting was primarily accomplished by a "ladder/sack" harvesting system. In such a harvesting system, a ladder is strategically positioned, or supported against, a tree so that the upper end of the ladder is located adjacent a fruit-bearing portion of the tree. A worker carrying a sack then climbs up the ladder, picks the appropriately ripened fruit within a reachable area surrounding the upper end of the ladder, and places the picked fruit into his carrying sack. When all the fruit within the reachable area has been collected, the worker climbs down from the ladder and empties the fruit in his sack into a pallet tub. The ladder is then repositioned so that its upper end is located adjacent another fruit-bearing portion of the same or a different tree and the process is repeated.
In recent years, the scarcity and/or increased cost of labor has spawned a variety of mechanical harvesting systems designed to efficiently use the efforts of workers hand-picking the fruit. One such machine is disclosed in the above-identified parent application. This machine includes a supporting vehicle, a hopper mounted on the vehicle, an extendable/retractable boom rotatably mounted on the vehicle, and a worker-supporting bucket attached to the distal, or outer, end of the boom.
In operation, the vehicle would be driven to the appropriate section of the orchard and a worker would be stationed inside the worker-supporting bucket. The boom would then be extended/ retracted to a position whereat the bucket, and the worker stationed therein, would be adjacent a fruit-bearing portion of the tree. The necessary extension/retraction of the boom is accomplished primarily by an inner boom section, a middle boom section and an outer boom section, these sections being telescopically coupled to each other whereby many extension/retraction patterns are possible.
The machine further includes a conduit system which extends from the bucket, through the boom, and to the hopper. In this manner, the worker stationed inside the bucket may pick fruit from a reachable area surrounding the bucket and place such fruit in a trough connected to the outer end of the conduit system. The conduit system pneumatically conveys the fruit from the bucket to the hopper. Because a portion of the conduit system, namely the upper conduit arm, extends through the extendable/retractable boom, this upper conduit arm must also be capable of extending and retracting. As such the upper conduit arm is comprised of an inner conduit section, a middle conduit section and an outer conduit section, and these conduit sections are telescopically coupled to each other.
Perhaps at this point it should be noted that the term "inner" in this context corresponds to the boom/conduit section positioned closest to the vehicle; the term "outer" corresponds to the boom/ conduit section positioned closest to the bucket; and the term "middle" corresponds to the boom/conduit section positioned therebetween. Additionally, the boom sections and the conduit sections, respectively, increase in transverse size from the outer section to the inner section. As such, the inner boom/conduit section has the largest transverse size and the outer boom/conduit section has the smallest transverse size.
Of particular concern in the present application is the coupling of the conduit sections to each other. In the machine disclosed in the parent application, the outer conduit section and the middle conduit section have a coupling therebetween which permits relative sliding movement between the outer and middle conduit sections but limits outer extension of the outer conduit section relative to the middle conduit section. The middle conduit section and the inner conduit section include a similar coupling therebetween which permits relative sliding movement between the middle conduit section and the inner conduit section but limits the outer extension of the middle conduit section relative to the inner conduit section. These couplings are of a rather bulky design because they are adapted to withstand the stresses of the extension/retraction of the upper conduit arm.
Another issue of particular concern in the present application is the support of the upper conduit arm during the extension/retraction of the boom. The conduit sections which form the upper conduit arm are typically made of a thin plastic material, and such a design advantageously minimizes the weight of the boom/conduit assembly. However, such a design also disadvantageously results in the conduits having very little bending strength whereby an significant deflection of the conduit sections may have a damaging effect. Moreover, significant deflection of the conduit sections may result in misalignment between the conduit sections which will impede the efficient travel of the fruit therethrough.
In the machine disclosed in the parent application, the outer end of the outer conduit section is fixedly mounted to the outer end of the outer boom section. Additionally, the inner end of the inner conduit section is fixedly mounted to the inner end of the inner boom section. Thus the upper conduit arm will always be supported at its inner and outer end, regardless of the extension/retraction pattern of the boom.
The machine additionally includes a first deflection-preventing member which is mounted on the inner end of the middle boom section and which is sized to cradle the inner conduit section. This first deflection-preventing member will slidably support the inner conduit section and the point of this support will depend on the particular extension/retraction pattern of the boom. For example, if the middle boom section is fully retracted relative to the inner boom section, the first deflection-preventing member will cradle and slidably support, the inner end of the inner conduit section. Alternatively, if the middle boom section is fully extended relative to the inner boom section, the first deflection-preventing member will cradle, and slidably support, the outer end of the inner conduit section.
The machine further includes a plug-groove assembly for supporting the outer end of the middle conduit section. This plug-groove assembly comprises a pair of plugs which extend radially outwardly form the outer end of the middle conduit section. A mating groove is provided for each plug in the outer boom section whereby as the middle conduit section moves relative to the outer boom section, the plugs will be positioned at different locations on the grooves. For example, when the middle conduit section is retracted and the outer boom section is extended, the plugs will be positioned at the inner ends of the grooves. Alternatively, when both the middle conduit section and the outer boom section are fully retracted, the plugs will be positioned at the outer ends of the grooves.
While the support arrangement of the machine disclosed in the parent application performs reasonably well in most extension/retraction patterns, certain complications are now contemplated when the machine is in a particular extension pattern. This particular extension pattern occurs when:
(i.) the middle boom section is fully retracted relative to the inner boom section; PA1 (ii.) the outer boom section is fully extended relative to the middle boom section; PA1 (iii.) the middle conduit section is fully extended relative to the inner conduit section; and PA1 (iv.) the outer conduit section is fully retracted relative to the middle conduit section, but fully extended relative to the inner conduit section. PA1 (i.) the middle boom section is fully retracted relative to the inner boom section; PA1 (ii.) the outer boom section is fully extended relative to the middle boom PA1 (iii.) the middle conduit section is fully extended relative to the inner conduit section; and PA1 (iv.) the outer conduit section is fully retracted relative to the middle conduit section, but fully extended relative to the inner conduit section.
In such an extension/retraction pattern, the upper conduit arm is supported at only two points: its outer end and its inner end. Specifically, as in all extension/retraction patterns, the inner conduit section is fixedly secured to, and thus supported by, the inner end of the inner boom section and the outer conduit section is fixedly secured to, and thus supported by, the outer end of the outer boom section. While the machine also includes the first deflection-preventing member and the plug-groove assembly, in this particular extension/retraction pattern these components also support the upper conduit arm at its outer end and at its inner end. More specifically, in this extension/retraction pattern, the plugs will be positioned at the outer ends of the grooves. Additionally, because the middle boom section is retracted relative to the inner boom section, the first deflection-preventing member will cradle, and slidably support, the inner end of the inner boom section. Consequently, this extension/retraction portion leaves the central portion of the upper conduit without support thereby increasing the probability of premature failure. This problem is believed to be aggravated by the weight of the bulky coupling between the inner conduit section and the outer conduit section.
One solution which was considered by applicant to eliminate this complication was the addition of a second deflection-preventing member to support the middle portion of the upper conduit arm when the above-described extension pattern is encountered. Applicant contemplated designing the second deflection-preventing member so that it would be similar to the first deflection-preventing member which is mounted on the inner end of the middle boom section. In such a similar design, the second deflection-preventing member would be adapted to be mounted on the inner end of the outer boom section and would be designed to support cradle the middle conduit section. In this manner, the second deflection-preventing member could support the central portion of the upper conduit arm in the above-described and other extension/retraction patterns.
However, modifying the machine to include a second deflection-preventing member of this design proved to be unworkable in actual practice for several reasons, most of which relate to the inability of the boom to telescope in the intended manner. For example, if the second deflection-preventing member were sized to cradle the middle conduit section, this would prevent the middle boom section from being retracted relative to, or telescoped within, the inner boom section. This prevention is due to the fact that the second deflection-preventing member would be unable to travel past the bulky coupling between the inner conduit section and the middle conduit section. Moreover, even if the second deflection-preventing member could travel past this bulky coupling, a rigid member would not be able to make the transition between the middle conduit section to the inner conduit section (which has the largest cross-sectional size of the three conduits) during the retraction process.
Applicant therefore believes a need remains for a harvesting machine which provides adequate support for the upper conduit arm in virtually all extension patterns